Refrigerating apparatus



Jan. 3, 1939. H. SMlTH 2,142,828 REFRIGERATING APPARATUS Original FiledAug. 28, 1930 2 Sheets-Sheet l ATTOR Jan. 3, 1939. F WTH 2,142,828

REFRIGERAT ING APPARATUS Original Filed Aug. 28, 1930 V v v ATTORNEY 2Sheets-Sheet 2 Patented Jan. 3, 1939 PATENT OFFICE BEFRIGERATINGAPPARATUS Harry F. Smith, Dayton, Ohio, assignor, by mesne assignments,to General Motors Corporation, a corporation of Delaware ApplicationAugust 28,

1930, Serial No. 478,390

Renewed September 28, 1935 17 Claims.

This invention relates to refrigerating apparatus and more particularlyto improved apparatus for the cooling of liquids.

One of the objects of this invention is to provide an improvedmechanically operated apparatus for the cooling of liquids and toarrange said apparatus in such a manner so that the mechanicallyoperated means will not frequently be rendered operative.

Another object is to provide an improved apparatus for the cooling ofliquids, and to provide means for preventing destructive freezing ofsaid apparatus. I

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the invention is clearly shown. 1

In the drawings: Fig. 1 is a diagrammatic illustration, partly elevationand partly in cross-section, of a refrigerating apparatus embodyingfeatures of this invention;

Fig. 2 is a diagrammatic illustration of a modifled form ofrefrigerating apparatus embodying features of the invention; and 1 Fig.3 is a top view in cross-section of the apparatus shown in Fig. 2, theview being taken on the line 3-4 of Fig. 2.

An apparatus for the cooling of liquids, ac-' cording to this invention,includes a primary refrigerating system 20 for maintaining a relativelylow temperature such as for freezing, and a secondary refrigeratingsystem 22 for the maintenance of a higher refrigerating temperature suchas is suitable for cooling of liquids to be used as beverages. Thermalheat exchange means 24 including the condenser 25 for the secondarysystem and a gas, such as air, noncondensable at-temperatures prevailingin the secondary system are provided in the secondary system formaintaining the temperature differen- -tial with respect to the primarysystem in accordance with the change of temperature of the main body ofliquid refrigerant in the secondary system. By this arrangement thetemperature in the secondary system is maintained substantially constantas is more. fully hereinafter described, to thus prevent destructivefreezing. of the liquid supply apparatus for the liquids to be cooled.In order to prevent frequent operation of the primary refrigeratingsystem I have provided a holdover composition 28 which preferablyfreezes during the operation of said system at a point intermediate thestarting and stopping of said system. This holdover composition ispreferably an eutectic mixture, the entire body of which freezes at onetemperature and which tends to delay the evaporation of refrigerant inthe primary system.

Referring more in detail to the drawings, the primary refrigeratingsystem 20 comprises in general a finned liquid refrigerant evaporator 30of the flooded, float controlled type, and a refrigerant liquefying unit3|. The evaporator 30 is located in the chamber 32 surrounded by theholdover composition. The liquefying unit 3| withdraws the gaseousrefrigerant from the vapor conduit 35, liquefies the refrigerant anddelivers it to a supply conduit 36. The liquefying unit includes themotor 31, compressor 38, and condenser 39, the motor being controlled inresponse to pressure within the conduit 35 and therefore in accordancewith the temperature of the body of liquid refrigerant in evaporator 30by means of an automatic switch 42 which connects the motor with thepower mains 43. to maintain, normally, the said temperature withinpredetermined limits.

The secondary refrigerating system 22 comprises in general a vaporizeror evaporator 50 formed by a metallic member SI and containing a body ofliquid volatile refrigerant, such as S02. As previously stated hereinthe heat exchange means 24 includes a condenser 25 of the secondarysystem. Preferably the heat exchange means 24 includes a closed conduitcontaining a volatile refrigerant. The conduit is provided with a coiledportionjlocated preferably, below the level of refrigerant in theevaporator 30, and a coiled portion forming the condensing surface ofthe condenser 25. The condenser of the secondary system is provided witha closed, long and relatively narrow passageway 55 formed above thevaporizer 50. The passageway "is provided with a gas pocket for the gasnoncondensable at temperatures prevailing in the apparatus, which gas isprovided in said secondary system in the passageway 55. Preferably theholdover chamber 22 and the vaporizing chamber 50 are insulated from theexterior and from one another by insulation 62,

The secondary refrigerating system 22 is adapted for the cooling ofliquids, for instance, water. Preferably the water is cooled by passingthrough a conduit which is in contact with the liquid refrigerantcontained in the .vaporizer in the secondary system. The conduit isprovided with a bubbler 61, and a valve I by which the liquid to becooled is subject to demand intermittently at variable rates. Theconduit 55 may be connected to any suitable water pressure system and ispreferably of such a length that water passing therethrough will bechilled to a temperature equal that of the liquid refrigerant in thevaporizer by the time the water passes through the entire length of saidconduit.

The operation of my improved apparatus for the cooling of liquids isasfollows. When the valve 68 is intermittently operated for withdrawingwater through the bubbler 57, the water entering the conduit 55 is abovethe temperature of that to which it is finally cooled, thus giving upits heat directly to the metal wall of the conduit 65 and the latter inturn delivers this heat to the liquid refrigerant surrounding it withthe result that some of the liquid refrigerant in contact with theconduit is vaporized and rises through the liquid refrigerant to thepassageway 55. When this occurs a varying capacity of the condenser isobtained by the driving of said noncondensable gas in the pocket of thepassageway 55 in accordance with the change of temperature of the liquidrefrigerant in the secondary system. That is, the increased temperatureof the liquid refrigerant in the vaporizer 50 increases the amount ofevaporation in said vaporizer which in turn increases the pressureacting on the noncondensable gas in the passageway 55. As said pressureincreases, the gas in the passageway 55 will be swept along thecondensing surface of the condenser 25 by f'the rapid action of theevaporated refrigerant from the vaporizer 50. Since the passageway 55 isrelatively narrow, the gas will be swept ahead of the rapidly movingevaporated refrigerant and in so doing said gas will be compressed. tothus allow the evaporated refrigerant to uncover only the proper amountof condensing surface of the' condenser. The area of thepassageway 55 issufficiently small so that the rate of the diffusion of the evaporatedrefrigerant into the gas is considerably less than the velocity of therefrigerant vapor rushing upwardly to the condenser 25 to be condensed.As the condenser condenses the evaporated refrigerant sufiiciently toreduce the temperature of the liquid refrigerant in the vaporizer 50,the pressure on the gas will decrease, thus permitting saidgas to expandto thereby gradually cover the condensing surface to gradually reducethe rate of condensation. This arrangement limits the condensing actionof the secondary system to thus maintain the desired temperature, withinpredetermined limits, of the liquid refrigerant in the vaporizer 50.From the foregoing it will be noted that the evaporated refrigerant fromthe evaporator of the secondary system uncovers a varying proportion ofthe condensing surface of the condenser by sweeping the noncondensablegas into the passageway 55 ahead of the evaporated refrigerant inaccordance with the change of temperature of the liquid refrigerant inthe vaporizer 50 of the secondary system. Thus the action of thecondenser 25 is such that it maintains a substantially constanttemperature in the vaporizer 50 regardless of the particular lowertemperature of the condenser 25 or evaporator 30 by presenting thecorrect amount of condensing surface to the vaporized refrigerant of thesecondary system.

In order to obtain different predetermined limits of temperature for themain body of liquid refrigerant in the vaporizer 50 the amount orquantity :f the uncondensable gas may be varied.

The more noncondensable gas used the higher the temperature will be ofthe liquid refrigerant in the vaporizer 55.

During the condensing action of the secondary system the heat istransferred by the heat exchange means 241 to the liquid refrigerantcontained in the evaporator 30. However, the running operation of theprimary system is limited by the holdover composition which surroundsthe evaporator 30. Preferably the holdover composition is a eutecticmixture, the entire body of which freezes at one temperature and duringone cycle of the operation of the primary system at a point intermediatethe starting and stopping temperature thereof. When the holdovercomposition is in frozen condition it will tend to delay the evaporationof the refrigerant in the evaporator 30 to thus prevent frequentoperation of the liquefying unit 3!.

Referring now to Figs. 2 and 3 there is shown a modified form of liquidcooling apparatus designated in general by the numeral 70. The apparatusit includes a primary refrigerating system l2 and a secondaryrefrigerating system 14. The primary refrigerating system comprises ingeneral a finned liquid refrigerant evaporator 16 of the floatcontrolled type having conduits TI and 18 which may be connected to arefrigerant liquefying unit of the type shown in Fig. 1. The evaporatori6 is surrounded by a holdover composition 19 preferably a eutecticmixture. The secondary refrigerating system comprises in general avaporizer or evaporator 86 containing a body of liquid volatilerefrigerant, such as 802. above which is a body of gas, such as air,noncondensable at temperatures prevailing in said secondary system. Thesecondary system 14 is adapted for the cooling of liquids. The liquidsto be cooled are circulated through a metal vconduit 82 in contact withthe liquid refrigerant in the vaporizer 80. The evaporator 12, holdoversolution and vaporizer are insulated from the exterior and theevaporator 12 and holdover composition are insulated from the vaporizerby insulation 9)).

Thermal heat exchange means 9| for the systems I2 and 74 includes thecondenser for the secondary system, which heat exchange means in thiscase is a wall between the evaporator of the primary refrigeratingsystem and a space 94 for gas noncondensable at temperatures prevailingin the secondary system. The space 94 provides a gas pocket for saidgas. When evaporation of refrigerant in the secondary system takesplace, the varying capacity of the condenser is obtained by theconcentration of said gas in'the space 94 substantially as in Fig. 1.Thus it will be noted that the evaporated resystem uncovers a varyingproportion of the condensing surface by sweeping the gas in the space 94ahead of the evaporated refrigerant in accordance with the change oftemperature of the liquid refrigerant in the vaporizer 80 of thesecondary system. As shown in Fig. 3, the part of the heat exchangemeans serving as a condenser for the secondary system is in the form ofa cormgated wall. This arrangement provides an ample condensing surface.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A refrigerating apparatus including a primary refrigerating systemincluding a primary liquefying apparatus and a primary evaporatingmeans, a secondrefrigerating system having a heat exchange means forcooling a substance to be cooled, a congealingv solution in heat exe,relationship with said primary evaporating means, said congealingsolution and the primary evaporating means being surrounded byinsulation, and a heat exchange coupling for thermally connecting ,theprimary evaporating means and the second refrigerating system.

2. A refrigerating apparatus including an enclosure including a liquidchamber containing a Volatile liquid and a vapor space above the liquid,said enclosure including a narrow passage located above the level of thevolatile liquid and connected to the vapor space, a dead end pocketconnected to the other end of the narrow passage, an evaporating meanslocated in the narrow passage, said enclosure containing an-inert gas,said enclosure also containing heat exchange means in heat exchangerelation with the volatile liquid in the liquid chamber.

3. A refrigerating apparatus comprising a pri- 'mary refrigerant zone,a'primary refrigerant for maintaining said zone within predeterminedtemperature limits, a secondary refrigerant syserant in its flow intosaid passageway.

'7. Refrigerating apparatus comprising means forming a long relativelynarrow passageway closed at its upper end and connected to a reservoirbelow said passageway at the lower end, a body of liquid volatilesecondary refrigerant in said reservoir, a primary refrigerating systemconnected to cool said passageway, inert gas in 1 said passageway, saidpassageway being so protem, said system including a liquid body of sec-'ondary volatile refrigerant, a relatively inert gas uncondensable atprevailing temperatures and a casing containing said secondaryrefrigerant and gas and including a relatively narrow passageway inthermal contact with said primary refrigerant zone and a dead end-pocketbeyond said narrow passageway, the size of said passageway being suchthat when secondary refrigerant is evaporated from said liquid body, theresultant flow of gaseous secondary refrigerant int said passagewaysweeps said inert gas into s d pocket at a rate faster than the rate ofdiffusion of said inert gas.

4. A refrigerating apparatus comprising a primary refrigerant zone, aprimary refrigerant for maintaining said zone within predeterminedtemperature limits, a secondary refrigerant system, said systemincluding a liquid body of secondary volatile refrigerant, a relativelyinert gas uncondensable at prevailing temperatures, and a casingcontaining said secondary refrigerant and gas portioned that said inertgas is swept toward said closed end by the velocity of gaseousrefrigerant in its flow into said passageway, and means controlling theoperation of said primary refrigerating system in acordance with changesin refrigeration conditions.

8. In combination, a primary refrigerant sys- V tem having a heatexchange surface, an inert gas blanketing a portion of said surface, asecondary refrigerant system in thermal exchange relationship with saidsurface, and means whereby a variation in the temperature-pressurerelationship of the refrigerant in said secondary system causes avariation in the blanketing action of the inert gas.

9. In combination, a primary refrigerating system including a primaryevaporator, a secondary refrigerating system including a secondarycondenser in thermal exchange relationship with said primary evaporator,and means responsive to the temperature-pressure relationship of therefrigerant in said secondary system for varying the amount of surfacearea of said condenser which is exposed to the secondary refrigerant.

10. In combination, a primary refrigerating system including a primaryevaporator, a secondary refrigerating system including a secondarycondenser in thermal exchange relationship with said primary evaporator,a low pressure refrigerant in said secondary refrigerating system,

and including a relatively narrow passageway in thermal contact withsaid primary refrigerant zone and a dead end pocket beyond said narrowpassageway, the size of said passageway being such that when secondaryrefrigerant'is evaporated from said liquid body the resultant flow ofgaseous secondary refrigerant into said passageway sweeps said inert gasinto said pocket at a rate faster than the rate of diffusion of saidinert gas, and in varying degrees in accordance with the rate ofevaporation of volatile secondary refrigerant from said liquid body.

5. Refrigerating apparatus comprising means passageway, said passagewaybeing so proportioned that said inert gas is swept toward said closedend by the velocity of gaseous refrigerant in its flow into saidpassageway.

1 6. Refrigerating aparatus comprising means forming a long relativelynarrow passageway closed at its upper end and connected to a reserandmeans responsive to the temperature-pressure relationship of therefrigerant in said secondary system for varying the amount of surfacearea of said condenser which is exposed to the secondary refrigerant.

11. In combination, a chamber containing a low pressure volatilerefrigerant, a relatively narrow passage leading upwardly from saidchamber and containing inert gas, and a condensing surface intermediatethe ends of said passage whereby vaporized refrigerant displaces theinert gas upwardly before coming in contact with the condensing surfaceand whereby the condensed refrigerant returns to the chamber with outpassing through the main body of inert gas.

12. The method of refrigeration which comprises evaporating refrigerantin a first zone, leading the refrigerant vapor into a. second zone andinto heat transfer relation with a condensing surface substantiallysurrounded by a relatively inert gas uncondensable at the prevailingtemperatures, and utilizing the uncondensable gas to control the heattransfer relation between said I vapor and said condensing surface.

13. In a refrigerating system, an evaporator having a passage connectedthereto, a condenser in said passage, inert gas normally surroundingsaid condenser, said passage being so arranged 1 that vaporizedrefrigerant displaces inert gas around said condenser, condenses andreturns to the evaporator without passing through the main body of inertgas.

14. In a refrigerating system, an evaporator, a condenser complementaryto said evaporator, means for progressively blanketing portions of theexterior surface of said condenser, said means serving to increaseltheeffective condensing surface of said condenser up'on an increase inrefrigerant demand. 15. The method of refrigeration which comprisescooling a surface in a first zone, causing evaporation in a second zone,surrounding a: portion 'of said cooling surface by a. relatively inertgas uncondensable at the temperatures prevailing in said zones, leadingthe vapors formed in said second zone into heat transfer relation tosaid cooling surface and utilizing said uncondensable gases forcontrolling the transfer of heat of said vapor to said cooling surface.

greases between said zones.

17. In combination, a refrigerant system having a heat exchange surface,means blanketing a portion of said surface, a secondary refrigerantsystem in thermal exchange relationship with said surface, and meanswhereby a. variation in the temperature pressure relationship of therefrigerant in said secondary system causes a variation in theblanketing action of said first named HARRY F. SMITH.

